# Ene-Allenes: Access from Dialkynes by an Intramolecular anti-Carbopalladation Cascade

## TL;DR

A new palladium-catalyzed reaction creates complex ene-allenes from dialkynes, forming multiple carbon-carbon bonds efficiently.

## Contribution

A novel intramolecular palladium-catalyzed cascade combining anti- and syn-carbopalladation is introduced for ene-allene synthesis.

## Key findings

- The cascade reaction forms two new carbon–carbon bonds across the first double bond.
- The process terminates via β-hydride elimination from a vinyl Pd(II) complex.
- Diverse ene-allenes in oligo(hetero)cyclic systems are synthesized with up to 73% yield.

## Abstract

Herein, an intramolecular palladium-catalyzed cascade
reaction
is reported consisting of both formal anti-carbopalladation
and syn-carbopalladation of internal alkynes. This
process leads to two new carbon–carbon bonds across the first
double bond formed. The cascade is terminated by β-hydride elimination
from the emerging vinyl Pd­(II) complex. As a result, di-, tri-, and
tetrasubstituted ene-allenes embedded in an oligo­(hetero)­cyclic ring
system are synthesized in yields of up to 73%.